Insulation piercing electrical connectors



Oct. 29, 1968 A. GREENBAUM 3,408,616

INSULATION PIERCING ELECTRICAL CONNECTORS Filed April 21, 1966 4 Sheets-Sheet l INVENTOR r2 ur wen6aum Y W i ATTORNEY Oct. 29, 1968 A. GREENBAUM INSULATION PIERCING ELECTRICAL CONNECTORS 4 Sheets-Shet 2 ldAp 1 1 1966 FIG 2 Oct. 29, 1968 GREENBAUM s R O T c E N N O c L A C T. R

INSULATION PIERCING ELECT 4 Sheets-Sheet 5 Filed April 21, 1966 FIG A. GREENBAUM INSULATION PIERCING ELECTRICAL CONNECTORS 66 Get. 29, 1968 4 Sheets-Sheet 4 Filed April 21, 19

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[ll/l 26 F I G I United States Patent Filed Apr. 21, 1966, Ser. No. 544,304 8 Claims. Cl. 339-99 ABSTRACT OF THE DISCLOSURE This invention provides a new electrical connector of the insulation-piercing type, which automatically makes n with a flexible electrical conductor by -impaling the Academy Electriprobing the dielectric covering and pressur Statement of invention The invention is exemplified by an electrical male terminal two rivets, hence facture of the old riveted wlring-core (FIG. 1 in the patent). It is now improved and made Rivetless, as shown in the accompanying drawings and briefed in the and second summaries, the next two topics, as follows:

Old body part 11 changed to new body part 4 First, in implementing the aforesaid purposes, the molded plastic old body part 11 (FIG. 1 in the patent) is reformed to provide a new body part (two required), which is characterized by:

(l) Eliminating the two rivets that heretofore held the two old twin body half parts 11 together;

(2) Reforming the molded shape of the old body part 11, to produce the new twin body half parts, numbered 4 and 4a herein;

(3). Providing improved centering means which positions (aligns) ing relation, preliminary to being out rivets, to form and 4a;

(4) Providing two new of the new body part;

3,408,616 Patented Oct. 29, 1968 in FIG. 9 and other views of my prior patent. Old contact blade 3 changed to new contact blade .18

Second, in further implementing the aforesaid purpose, the die-formed old lever-type, plug-in, contact blade 3 (FIG. 1 in the patent is reconstructed to provide a new contact blade 18 (two required), which is characterized by:

(1) Providing a new clamping yoke on the inner (rear) end of the old contact blade 3 to arms that clamp the twin body parts together; since there are two new contact blades (twins), it follows that there are four clamping arms which positively clamp the body parts together, thus effectively performing the function of the omitted rivets;

(3) Each parallel clamping arm is provided with a new pivot trunnion, hence four trunnions, that articulate in the pivot bearings of the new two-part body;

(4) Each parallel clamping arm, four arms, has an inner edge slide-bearing that rides on its respective surface slide-bearing of the two-part body. Accordingly, these eight slide-bearings (four on the two-part body and four on the two contact blades) serve a new function, that of guiding the two new articulated contact blades with such old pressure-impaling barbs (9 in FIG. 1 of the patent) are precisely held to the planes piercing barb 9 9 in the patent) togetherhyvithout rivets, thereby solving,the..rine prob-.....

lem; and

(b) Also, guiding the articulated twin barbs in their exact planes. of; closing movement. which pierces, with certainty, at or close to the center of the wire strands of the conductor, thereby improving the mode of operation. .In generaLthis new wiring-core Comprises one molded dielectric (plastic) body part and one die-formed levertype plug-in, contact blade, hence two parts. However,

since tw o of each part are required, my new wiring-core assembly comprises four parts. They are self-captive, i.e., hold each other together and cannot readily be taken apart, unless broken., f l V 'The new twin contact blades extend forwardly from the frontend of the rivetless wiring-core, and my old,- di electric slide-on cap is pushed onto its rear end and encloses the parts.

The drawings The accompanying four sheets of drawings are made from a specimen adapted for. production and enlarged for clarity on a scale somewhat more than three times actual size.

FIGS. 1 to 7 illustrate the new wiring-core; and FIGS. 8 to 11 show the connector made complete by mounting the oldslide-on cap (of my prior patent) on the new wiring-core.

FIG. 1 (sheet 1) illustrates the four components in spaced-apart assembly alignment.

'The next group of four views shows the molded twin body parts (noted centrally in FIG. I) placed in face to face position, with a centering means of one twin disposed in the centering means of the other. i '"By centering means is meant an arrangement of two sockets and two bosses, in staggered relation, on the inner faces of the twin body parts which register and snugly interfit with each other to align and hold the twin body parts against sliding displacement, preparatory, to being clamped together.

FIG. 2 shows the molded twin body parts of FIG. 1 stacked together, thus a complete two-part body unit. The left hand portion (small end) is the front end and may be referred to as the trunk. The central portion is the neck. And the right hand end (large end) is the head constituting the rear portion of the wiring-core.

FIG. 3 is a transverse section on the line, 3 at the front end of FIG. 2, showing the trunk centering means.

FIG. 4 is a transverse section through the neck on theline 4 of FIG. 2,'showing a barb opening into the wire passage, one barb opening on each side of the twopart body.

FIG. 5 is a transverse section on the line 5 of FIG. 2

at the rear end through the head, showing a coaxial.

unique arrangement of combined centering means and pivot bearings.

The next three are action views, three assembly steps, which demonstrate how a clamping yoke, its two arms, formed on the rear (inner) end of each articulated twin lever-type, contact blade, is mounted on the two. mated twin body parts to permanently clamp them together.

FIG. 6A shows the first assembly step. The two parallel clamping arms are being started into clamping and articulated position onto the aforesaid surface slide-bean ings of the two-part body. The horizontal arrows on the arms show the direction of force applied (either manually or by an assemblying machine), that pushes them into final position; and

FIG. 6B shows the two clamping yoke arms elastically stressed apart edgewise in the direction of the arrows (without exceeding their elastic limits), and they are sliding rearwardly' on the surface slide-bearings of the two-part body; while finally FIG. 6C shows that the two yoke clamping arms have reached their final position and have spring snapped their pivot trunnions into the two pivot bearings of the mated body parts, for irremovably clamping them together.

pleted wiring core.

Note that the preceding three views show the method of clampingly mounting one twin contact blade on the new two-part body, and that theother twin contact blade is mounted in the same Way} In manufacturefboth contact blades may be pushed into final articulated clamping position t,one,time by an autornatic assemblinggmachine. FIG. 7 shows the completed assembly of my newfrivetless wiring=core, which may. now be; compared to the old riveted wiring-core (FlGflain my prior patent). The contact blades are open in readiness to receive the blunt end of a two stranded-wire, insulation-covered, flexible conductor cord; I f r I FIG. 8 shows my old slide-on cap, with the conductor cord. inserted through it. ,Theend of thewire, protruding through the. cap, is,about to be insertedginto the new wir ing-coreshown in FIG. 7. Thereupon, the twin -lever-type contact blades are closedv by thumb-and-forefing er pressure. The old slide-on cap is then pushed onto the wiringcore and snubsthe conductor cord for strain relief, as in the next view. I

FIG. 9 is a lengthwise section of the complete connector, looking down on the edges of the twin lever-type contact blades. The old slide-on cap is in section, the new wiring-core in elevation, and the flexible. conductor cord is snubbed in place. 1

FIG. 10 is a lengthwise section on line 10 of FIG. 9, looking sidewise at the fiat surface of one of the contact blades.

FIG. 11 is a greatly enlarged transverse section online 11 of FIG. 10 through the neck of the mated body parts. This view shows the exactness with which the aforesaid slide-bearings serve to precisely guide the two articulated contact barbs into pressure-piercing electrical connection with the respective insulation-covered wire strands'of a two-wire conductor. a,

The foregoing specification discloses the invention, but a brief detailed description is next made by further references to the part numbers and legends on the drawings.

New body part 4 and its duplicate body 4;:

In the drawings, the new body part 4 is molded of hard dielectric plastic, with an enlarged rear end (the head), also a reduced size central portion (a neck), and front end portion (a trunk). Its mate or twin part 4a is iden tical. Accordingly, the part numbers are the same on the two body halves, except for 4a on one of the twins for identification in this description. 7

A centering boss 5 and a centering socket 6 are molded on and in the inner face of the trunk, i.e., the front smaller end of the body parts 4 and 4a. It is seen that if the two inner faces are placed together (FIGS. 2 and 3), that the boss 5 of part 4 snugly fits into the socket 6 of part 4a. Thus 5 and 6 constitute a centering means for aligning the twin body parts at their front ends, thereby preventing relative sliding displacement between the two body halves 4 and 4a, which form a complete twopart body unit.

The head (enlarged rear end) is likewise provided with centering means for aligning the mated twin body parts 4 and 4a, and significantly, also for serving as pivot bearings which swingably mount the twin lever-type contact blades (as in FIG. 7). Thus, the centering means in the head (next paragraph) perform two-functions, whereas the boss 5 and socket 6 in the trunk (previous paragraph) perform one function. l

Accordingly, a boss 7 (FIG. 5) is molded on the inner face of the head of the body part 4 and snugly fits into the inner end of a thru-hole 8. The outer end of this thru-hole 8 provides a pivot bearing. Also, a pivot bearing recess9 is molded in the outer face of the body 4, coaxially with the boss 7.

Note, therefore, that the boss 7 and the inner end, only, of the thru-hole 8 constitute the centering means for the two head portions (rear ends) of the twin bodies 4 and 4a. It is noteworthy that the thru-hole 8 serves both as a centering means and as a pivot bearing.

Significantly, the outer end, only, of the thru-hole 8 (FIGS. 5, 6A, B, C) and the entire portion of bearing recess 9 constitute companion pivot bearings, in which and the thru-hole 8. This rangement is best observed in FIG. 1.

The next feature, in the head portion of the body 4, comprises two flat surface slide-bearings 10, symmetrically formed on each side and of less thickness than the neck,

bearings 10 are surface shaded for identity.

The twin surface slide-bearings 10 are formed on the plane of the longitudinal -8.X1S of the body 4. When the twin bodies 4 and 4a are 11), it is seen that the complete two-part body provides [four surface slide-bearings 10 (shaded), and that they are precisely parallel (FIG. 11). These four slide bearings coact with articulating contact blades, the next topic.

Two arm-pockets 12 are cformed on the outer surface of the head, one concentric with the thru-hole bearing 8, and the other concentric with the bearing recess 9. Each arm-pocket 12 extends upward from its surface slideone of the clamping contact blades, later are mated together.

A notch 14 is molded in one side of the neck of the body 4 and extends into the wire channel 13. This notch openings 14, one on each side, for entry of twin piercing barbs die-formed on the articulated contact blade 18, next described.

New contact blade 18 and its duplicate blade 18a with the new body unit 4, 4a

A metallic lever-type plug-in contact blade 18 embodies features noted in the second summary topic. Two contact blades 18 are required, hence twins; and

for enclosing the parts.

The front end 18 contact blade numbered 3 (FIG. 1 in my prior patent). Thus, the front ends 18 and 18a of the twin contact is conventional, the same as the old contact blades 18 and clamping yoke arms 22 are die-formed at crease the edgewise resiliency of the two clamping yoke arms 22, during their momentary spreading, when being permanently mounted on the two-part body 4 and 4a. This momentary resilient edgewise spread is demonstrated in FIGS. 6A, B and C and in the respective descriptions of these three action views.

of the slide-bearings 10. This is pointedly superior to other fastening means, such as rivets which localize the pressure against delicate plastic body parts, as in my prior patent.

slide (ride) bearon the body units wise axis of the contact blade 18, and have a loose fit in their respective pivot bearings 8 and 9. The trunnions 25 merely hold the contact blades 18 and 18a in place, whereas the exactness of the plane of articulation is achieved by the novel slide-bearing surfaces.

An impaling or piercing contact barb 26 is die-formed in the crotch of the yoke clamping arms 22. It is the same as the barbs 9 and 30 in my prior patent. But its plane of movement is improved, i.e., rendered more exact and constant by reason of the guided control of the articulated 18a performed by the eight surface slide-bearings 10 and 24.

The complete connector FIGS. 7 and 8 are referred to views) for final assembly of my old two-wire stranded conductor cord 32; and other known features are noted WhlCll cooperate with my new less wiring-core (FIG. 7).

Observe that the twin lever contact blades 18 and 18a are open (FIG. 7), and that the arm-pockets 12 stop the blades in full open position. The insulation-covered conductor cord 32 is now inserted through the rear en of the 'cap 30. The end of wire 32 which protrudes through the open end of the cap is next inserted all the way into the wire channel 13 of the wiring-core and the contact blades 18 and 18a are then manually closed. The yoke arms 22 stop against the neck of the body when the twin blades are closed.

I The twin barbs 26 on the contact blades pass through their respective openings 14 in the neck of the two-part body 4 and 4a and pierce the two-wire insulation, thus making a pressure-spreading contact with the respective wire strands (FIG. 11). Note that the twin bars pierce the wire strands at or close to center thereof. Hence, maximum current transmission is achieved.

Next, the front open end of my old cap 30 is pushed onto the rear end of the wiring-core (FIG. 7), and the two oppositely located latching shoulders 31 inside the cap catch against the detent latches 19 (FIG. 9) on the contact blades 18 and 18a, thereby securing the cap 30 in place. The sidewise spring fiexure, 'from the bends 20 along the length of the twin blades, act to detent latch the cap in place at 19 and 31. To remove the cap, the front ends of the blades are manually pressed toward each other for releasing the detent latch.

Observe that the four yoke arms 22 are disposed down in the arm-pockets 12 and below the outer surfaces of 'the twin body. Hence, the inner surfaces of the cap 30 make aclose slide-on fit with the wiring core body without engaging the yoke arms. The old cap 30 also snubs the flexible wire cord at 32a for strain relief (FIGS. 9 and in a manner similar to my prior patent.

It is readily appreciated that this new rivetless wiringcore contributes to economy in manufacture and achieves increased utility of the electrical connector.

What is claimed is:

1. An electrical connector comprising a body formed of twin body parts defining a channel therebetween to receive a two-wire conductor cord and two contact blades swingably mounted on said body, each of said body parts having a head, a neck and a trunk, centering means on the inner faces of said body parts, which interfit when said body parts are placed together in mated relation, thus maintaining said twin heads, necks and trunks in alignment, twin surface slide-bearings provided at the head ends of said twin body parts and pivot bearings molded in said head ends and being adjacent said surface slidebearings; each of said contact blades being provided with parallel yoke spaced apart clamping arms on its rear end, a pivot trunnion on the rear end of each clamping arm, and a piercing barb provided in the crotch of the yoke clamping arms, the spaced apart clamping arms embracing the mated twin body parts, thereby clamping them together, and the pivot trunnions being disposed in the pivot bearings, thus mounting the twin contact blades for articulation upon said body, the inner edges of the clamping arms being parallel with each other, thus constituting edge slide-bearings which swingably ride on said surface slide-bearings of the body to precisely guide the twin contact blades with their twin barbs in their fixed planes 8 into barb openings through opposite sides of the'neck of the body and into piercing contact with the strands of a two-wire conductor cord adapted to be inserted within said channel.

2 The electrical connector of claim 1, in which the pivot trunnions of the twin contact blades, disposed in the pivot bearings of the body, merely retain said contact blades in articulating position, while the coaction of the edge slide-bearings of the blades and the surface slidebearings of the body perform the double function of positively clamping'the twin body parts together, as well as confining the movement of each piercing barbto a constant and fixed plane aligned toward the center of the strands of a two-wire conductor cord adapted to be inserted within the wire channel. 1

' 3. The electrical connector of claim 1, wherein said centering means comprise, on the inner face of each body part, a boss and a socket in the trunk, and a boss and'a socket in the head, said bosses being disposed in staggered relation on opposite sides of said channel and likewise said sockets being disposed in staggered relation on or:-

osite sides of said channel.

4. The electrical connector ofclaim 1, having eight slide-bearing means, four on the clamping arms of the contact blades, and four on the twin body parts, for precisely guiding said twin piercing barbs in a fixed plane toward the center of the strands of a two-wire stranded conductor adapted to be inserted in the wire channel.

5. The electrical connector of claim 1 wherein each body part has a through-hole, the inner end of which constitutes a socket that receives a boss, and the outer end of which constitutes a pivot bearing which receives a sai pivot trunnion on the end of an arm of a contact blade.

6. The electrical connector of claim 1 wherein each pivot bearing is partially surrounded by an arm-pocket,

on the outer surface of the body, which opens toward its respective slide-bearing and has a depth that receives its respective arm down thereinto below the plane of the outer surface of the head, neck and trunk. I

7. The electrical connector of claim 1, in which the pivot trunnions are tapered to facilitate mounting said contact blades on the body.

8. The electrical connector of claim 1, in which said piercing barb is carried in the crotch of the spaced apart clamping arms and each inner edge of each arm is extended forwardly beyond the crotch in the form of parallel slits, to facilitate edgewise momentary spreading of the arms when mounting said contact blade on the body.

References Cited UNITED STATES PATENTS 2,673,968 3/1954 Smith -L- 339-99 2,769,154 10/1956 Greenbaum 339-99 FOREIGN PATENTS 993,178 10/1951 France.

MARVIN A. CHAMPION, Primary Examiner. I. H. MCGLYNN, Assistant Examiner. 

